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Ginkgo Biloba, a herb for the brain and cardiovascular health

Many herbs come and go depending on trends and new research, however ginkgo biloba has proven to be a consistently recognizable therapeutic herb within the healthcare community, with many clinical applications. Originating two hundred million years ago, Ginkgo is the world’s most ancient extant tree, and there have been hundreds of scientific studies done on this herb. Mordern scientific research support its traditional use by revealing the underlying molecular and clinical effects of ginkgo.

Vascular Effects and Circulation

The cardiovascular system is a continuous circuit of tubes carrying blood away from and back to the heart, which control blood flow and regulate circulation, which can be modulated by ginkgo. By keeping these vessels patent, adequate blood flow reaches each organ enabling perfusion of the organ for optimal function. Two main factors of the vasculature affect the overall delivery of blood flow to and from the tissues. Firstly, the walls of arteries and veins are compliant, albeit to different degrees, that allows for vessel calibre changes significantly affecting blood flow. Ginkgo has been found to have vasodilatory effects, which have been attributed to stimulation of endothelium-derived relaxing factor (EDRF) and prostacyclin release. Studies have suggested that Ginkgo inhibits nitric oxide, causing vascular relaxation including coronary artery vasodilation [1][2][3]. Secondly, the blood flowing through the tubes has its own set of properties that may be modulated by ginkgo to enhance blood flow and reduce clotting and plaque formation. Ginkgo potently inhibits receptor binding of platelet activating factor (PAF), which may mediate beneficial clinical effects [6][7]. PAF is pro-inflammatory and induces platelet aggregation during endothelial tissue injury. By inhibiting excessive platelet aggregation during atheromatous plaque formation, ginkgo may reduce the risk of atherosclerosis [5][6]. Acting similarly to aspirin in this respect, ginkgo may be beneficial in reducing atherosclerosis and arterial disease. Ginkgo has also been shown to have a clinical effect of active coagulation by reducing plasma D-dimer concentrations [4]. Clinically, by modulating vessel caliber and blood viscosity, ginkgo has been associated with reducing risk and severity of the clinical syndromes of peripheral arterial disease such as claudication [8], cerebral insufficiency [9] and vascular dementia [10-15].

Cognition – concentration, attention and memory

Healthy functioning of the brain requires adequate blood supply and nutrients, and effective neurotransmission. The cerebrovascular effects of improving blood flow to the brain are significant factors in enhancing cognition that have been discussed above, however ginkgo also modulates neurotransmitter systems in the brain associated with cognition and memory. Neuroprotective properties have been attributed to inhibition of age-related decline of adrenergic and cholinergic receptors. Ginkgo has been found to increase serotonin levels, increase muscarinic binding sites, and increase serum levels of acetylcholine and norepinephrine [16]. By improving blood supply to the brain and enhancing neurotransmission, ginkgo improves cognitive performance including enhancing concentration, attention and memory. This has been observed in healthy individuals as ginkgo has been shown to improve cognitive performance in a dose-dependent time-dependent manner [17], and older people with and without cognitive impairments such as dementia [10-15][17-18]. Additionally, many of the studies investigating cognitive performance benefits also reported significant improvements in stress levels, mood and wellbeing.

Sexual Health Performance

Sexual performance is multifactorial beginning with the psychological aspects of sexual desire, leading to the physical act of sex itself, involving adequate blood flow to the erect penis and to the clitoris for climax. Both the psychological effects of ginkgo on mood, wellbeing and reported sexual desire, and the vascular effects of increased blood flow and vessel integrity, are essential in the clinically proven effects of ginkgo on sexual performance [19-23]. Ginkgo has a positive effect on all 4 phases of the sexual response cycle: desire, excitement (erection and lubrication), orgasm, and resolution (afterglow).

Dosage Recommendations

Clinical trials have been done on various dosages for different clinical indication.

For cardiovascular benefits, a dose of 240mg/day was found to be significantly more beneficial than the lower dose of 120mg/day [24]. Another study showed that 120mg, but particularly the 240mg, single doses showed the most consistent central nervous system effects with an earlier onset (1 h) and longer duration (7 h) [25]. Therefore, for cardiovascular benefits, a dosage of 240mg per day of ginkgo would be recommended.

Multiple studies have been conducted with ginkgo biloba for cognitive enhancement in healthy people and those suffering dementia. Ginkgo has been shown to have both acute [17, 26] and chronic effects on cognition [27-30]. Again, these studies have been shown as dose dependent as the 240mg/day and 360mg/day showed superior results in a study measuring cognitive function in healthy people [17].

An average of 207mg of ginkgo was found to be significantly beneficial for both men and women in enhancing 4 areas of sexual performance in people currently taking antidepressants [31], therefore a range of 160-240mg per day is suggested for this indication.

The pharmacokinetic data of ginkgo show that the active ingredient of ginkgo biloba, ginkgolide B, has a half life (the time required for the plasma concentration of a drug to reach half of its original concentration, or for half of it to be eliminated from the bloodstream) of 10.6hrs, therefore ginkgo must be given at least twice daily to adequately maintain therapeutic levels of ginkgo. If patients take any Ginkgo product at a dose of one per day, they will have at least half a day unprotected by the product’s therapeutic effects.

The Future for Ginkgo

Overall, ginkgo biloba has been shown over the years to be significantly beneficial for circulation and the vascular system, as well as for cognition. Modern scientific research not only validates and supports these indications, but has also uncovered further benefits of ginkgo such as improving sexual performance, and characterized the active ingredient of ginkgo for more accurate dosing. Further studies may further support and elucidate the cardiovascular and neurological benefits, and uncover new effects for other indications of this valuable herb.

References

  1. Phytomedicine. 2008 Mar;15(3):164-9. Epub 2008 Feb 6.
    Ginkgo biloba extract improves coronary blood flow in healthy elderly adults: role of endothelium-dependent vasodilation.
    Wu Y, Li S, Cui W, Zu X, Du J, Wang F.
  2. Ginkgo biloba extract improves coronary blood flow in patients with coronary artery disease: role of endothelium-dependent vasodilation.
    Wu Y, Li S, Cui W, Zu X, Wang F, Du J.
    Planta Med. 2007 Jun;73(7):624-8. Epub 2007 Jun 13.
  3. Ginkgo biloba extract EGb 761 increases endothelial nitric oxide production in vitro and in vivo.
    Koltermann A, Hartkorn A, Koch E, Fürst R, Vollmar AM, Zahler S.
    Cell Mol Life Sci. 2007 Jul;64(13):1715-22.
  4. Effects of Ginkgo biloba on haemostatic factors and inflammation in chronic peritoneal dialysis patients.
    Kim SH, Lee EK, Chang JW, Min WK, Chi HS, Kim SB.
    Phytother Res. 2005 Jun;19(6):546-8.
    PMID: 16114087 [PubMed - indexed for MEDLINE]
  5. Ginkgolide B reduces inflammatory protein expression in oxidized LDL-stimulated human vascular endothelial cells.
    Zhang S, Chen B, Wu W, Bao L, Qi R.
    J CardiovascPharmacol. 2011 Mar 23. [Epub ahead of print]
  6. BiochemMolBiol Int. 1998 Dec;46(6):1243-8.
    Inhibitory effect of the leaf extract of Ginkgo biloba L. on oxidative stress-induced platelet aggregation.
    Akiba S, Kawauchi T, Oka T, Hashizume T, Sato T.
  7. J Ethnopharmacol. 1996 Mar;50(3):131-9.
    The neuroprotective properties of the Ginkgo biloba leaf: a review of the possible relationship to platelet-activating factor (PAF).
    Smith PF, Maclennan K, Darlington CL.
  8. Schweizer, J. and C. Hautmann, Comparison of two dosages of ginkgo biloba extract EGb 761 in patients with peripheral arterial occlusive disease Fontaine’s stage IIb. A randomised, double-blind, multicentric clinical trial. Arzneimittelforschung, 1999. 49(11): p. 900-4.
  9. Itil, T.M., et al., Central Nervous System Effects of Ginkgo Biloba, a Plant Extract. Am J Ther, 1996. 3(1): p. 63-73.
  10. Le Bars, P.L., et al., A placebo-controlled, double-blind, randomized trial of an extract of Ginkgo biloba for dementia. North American EGb Study Group. JAMA, 1997. 278(16): p. 1327-32.
  11. Le Bars, P.L., Response patterns of EGb 761 in Alzheimer’s disease: influence of neuropsychological profiles. Pharmacopsychiatry, 2003. 36 Suppl 1: p. S50-5.
  12. Scripnikov, A., A. Khomenko, and O. Napryeyenko, Effects of Ginkgo biloba extract EGb 761 on neuropsychiatric symptoms of dementia: findings from a randomised controlled trial. Wien Med Wochenschr, 2007. 157(13-14): p. 295-300.
  13. Iakhno, N.N., et al., [Tanakan (EGb 761) in the therapy of mild cognitive impairment]. Zh Nevrol Psikhiatr Im S S Korsakova, 2006. 106(12): p. 41-6.
  14. Allain, H., et al., Effect of two doses of ginkgo biloba extract (EGb 761) on the dual-coding test in elderly subjects. Clin Ther, 1993. 15(3): p. 549-58.
  15. Cieza, A., P. Maier, and E. Poppel, Effects of Ginkgo biloba on mental functioning in healthy volunteers. Arch Med Res, 2003. 34(5): p. 373-81.
  16. Can the cognitive enhancing effects of ginkgo biloba be explained by its pharmacology?
    Nathan P.Med Hypotheses. 2000 Dec;55(6):491-3.
  17. Kennedy, D.O., A.B. Scholey, and K.A. Wesnes, The dose-dependent cognitive effects of acute administration of Ginkgo biloba to healthy young volunteers. Psychopharmacology (Berl), 2000. 151(4): p. 416-23.
  18. Page, J.W., J. Findley, and M.A. Crognale, Electrophysiological analysis of the effects of ginkgo biloba on visual processing in older healthy adults. J Gerontol A Biol Sci Med Sci, 2005. 60(10): p. 1246-51.
  19. Wheatley, D., Triple-blind, placebo-controlled trial of Ginkgo biloba in sexual dysfunction due to antidepressant drugs. Hum Psychopharmacol, 2004. 19(8): p. 545-8.
  20. Wheatley, D., Ginkgo biloba in the treatment of sexual dysfunction due to antidepressant drug. Hum Psychopharmacol, 1999(14): p. 511-513.
  21. Cohen, A.J. and B. Bartlik, Ginkgo biloba for antidepressant-induced sexual dysfunction. J Sex Marital Ther, 1998. 24(2): p. 139-43.
  22. Yeh, K.Y., et al., Ginkgo biloba extract enhances male copulatory behavior and reduces serum prolactin levels in rats. Horm Behav, 2008. 53(1): p. 225-31.
  23. Yeh, K.Y., et al., Ginkgo biloba extract treatment increases noncontact erections and central dopamine levels in rats: role of the bed nucleus of the stria terminalis and the medial preoptic area. Psychopharmacology (Berl), 2010. 210(4): p. 585-90.
  24. Schweizer, J. and C. Hautmann, Comparison of two dosages of ginkgo biloba extract EGb 761 in patients with peripheral arterial occlusive disease Fontaine’s stage IIb. A randomised, double-blind, multicentric clinical trial. Arzneimittelforschung, 1999. 49(11): p. 900-4.
  25. Itil, T.M., et al., Central Nervous System Effects of Ginkgo Biloba, a Plant Extract. Am J Ther, 1996. 3(1): p. 63-73.
  26. Rigney, U., S. Kimber, and I. Hindmarch, The effects of acute doses of standardized Ginkgo biloba extract on memory and psychomotor performance in volunteers. Phytother Res, 1999. 13(5): p. 408-15.
  27. Cieza, A., P. Maier, and E. Poppel, Effects of Ginkgo biloba on mental functioning in healthy volunteers. Arch Med Res, 2003. 34(5): p. 373-81.
  28. Napryeyenko, O. and I. Borzenko, Ginkgo biloba special extract in dementia with neuropsychiatric features. A randomised, placebo-controlled, double-blind clinical trial. Arzneimittelforschung, 2007. 57(1): p. 4-11.
  29. Oken, B.S., D.M. Storzbach, and J.A. Kaye, The efficacy of Ginkgo biloba on cognitive function in Alzheimer disease. Arch Neurol, 1998. 55(11): p. 1409-15.
  30. Gessner, B., A. Voelp, and M. Klasser, Study of the long-term action of a Ginkgo biloba extract on vigilance and mental performance as determined by means of quantitative pharmaco-EEG and psychometric measurements. Arzneimittelforschung, 1985. 35(9): p. 1459-65.
  31. Cohen, A.J. and B. Bartlik, Ginkgo biloba for antidepressant-induced sexual dysfunction. J Sex Marital Ther, 1998. 24(2): p. 139-43.

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